<!doctype html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <style>
        .dot{
            display: inline-block;
            width: 60px;
            height: 60px;
            border-radius: 50%;
            background: #555;
            animation: loading 1s infinite ease-in-out;
        }

        @keyframes loading {
            0%,100%{
                transform: scale(0.0);
            }
            60%{
                transform: scale(1);
            }
        }
    </style>
 
        <div class="dot" style="animation-delay: -0s;"></div>
        <div class="dot" style="animation-delay: -0.3s;"></div>
        <div class="dot" style="animation-delay: -0.6s;"></div>
  

</body>

</html>